Mechanical Bending Strain-Actuated Modulation of Metal–Insulator Transition Temperature in Flexible Epitaxial V₂O₃ Films

In the era of the Internet of Things, flexible oxide electronics have been intensely investigated due to their unique advantages in portability, pliability, and stability. Among various oxide material systems, correlated electron materials (CEMs) have attracted significant attention, because they can display a broad range of intriguing phenomena such as colossal magnetoresistance, high-temperature superconductivity, and a metal–insulator transition (MIT). Tuning the electronic properties of CEMs featuring MIT behavior through the use of external stimuli is a prerequisite for developing CEM-based devices. Here we report a strong mechanical bending strain-actuated modulation of the MIT temperature (TMIT) in flexible V2O3/mica heterostructures. The epitaxial V2O3 thin films on flexible mica substrates were prepared by a pulsed-laser deposition (PLD) technique. Depending on the growth conditions, various lattice parameter ratios (c/a) and distinct different electronic transport properties were found in a series of V2O3/mica films. For the V2O3 films with c/a = 2.84 and 2.82, MIT behaviors were observed at TMIT ≈ 155 K and ≈ 172 K, respectively. Mechanical bending strain imposed from buckling the mica substrates was shown to remarkably modulate the TMIT (ΔTMIT ≈ 30 K) in these flexible V2O3 films. Additionally, we note that the bending response of TMIT in the V2O3 films relies on the applied bending strain direction. Bending cyclic tests manifest a good repetition of the experimental results and superior mechanical durability in flexible V2O3 films. The present work is highly instructive for flexible electronic device applications and provides an alternative platform for studying MIT behaviors of the CEMs in general.